Engine cooling system



Feb. 23, 1954 N A, J,.H ET AL 2,669,978

ENGINE COOLING SYSTEM Filed Ndv. 8, 1951 4 Sheets-Sheet l Jnventons attorneys F 23, 1954 A. J. HOVDE ET AL ENGINE COOLING SYSTEM 4 Sheets-Sheet Qttormys Filed Nov. 8, 1951 Feb. 23, 1954 A. J. HOVDE ET AL 2,669,978

ENGINE COOLING SYSTEM Filed NOV. 8, 1951 4 Sheets-Sheet 5 Inventors 1954 A. J. HOVDE ET AL ENGINE COOLING SYSTEM 4 SheetsSheet 4 Filed NOV. 8 1951 Patented Feb. 23, 1954 UNITED STATES PATENT OFFICE Brill, Cleveland, Ohio, assigno s to General Motors Cer'poration, Detroit, Milh, a corporafibn bf Delaware Application. Wovember -8, 1951, Seriai No. 255,478

9 Claims.

This invention relates to cylin'ders of two=eyc1e internal combustion engines and th'e like, and particularly to liquid cabling syst ms t erefor.

In two-Cycle engine cylinders having exhaust 'p'orts in the i'ow'er'p'a'rt of the cylinder side wall relatively high temperatures are developed at wideiy spaced points, i. e. in the cylinder walls ad'- jac'ent the ports, and in the combustion chamber walls of the cylinder head and cylinder u per end. This condition has created a problem in properly designing the coolant jacketine for such Cyliniiers aha heads, particularly those hi "the larger sizes and in which the head and cylinder barrel fbr'm an int'eg raJ unit, so as to avoid overheating and thermal strains in operation. Further, in the case of such engines whose cylinder units are basically designed to operate on either gas or oil (diesel) fue1, r a combination thereof, it is de sirab le that the provisions for coming be adapted for change to meet the temperature conditions encountered with either fu'e1, with-out necessitating the redesign 'of the basic com onents of the cylinder unit's. n I v v It is accordingly the pri'rloipai object bf our in"- vention to provide a cylir'i'tierh'ohstrirctibil haw ing improved means for cooling the exhaust ports to the extent desired in relation to the cooling of the cylinder head. In the main, We atempiis-h the desired result by the prqvismh of cylind'er coolant jakets above and below the-exhaust ports and partition t e of these jeekets, so as to effect a flow of coolant irtm a pqrti'bn t ereof through passages between certain of the e haust ports, into the other jacket space, the thence a reverse now from the latter through passages between the other exhaust ports ba'ck to the first jacket. 7 I, V H

In two-eyc1'e engine's employing 100p; scaveng- "ing the most convenient arrangement for mam folding the inlet and exhaustpor'ts'in the min-- der wall is to provide a housing which surrounds the cylinder opposite the port ring-s. As the port rings and consequently this inlet and exhaust housingare located time to the lower end hi the cylinder there "is usually insufficient space between this musin aha the crankcase hi the en gi'ne forintroci'ucing the cobiant into' thatpon tion of the Cylinder side Wail for i'iow" upward be tween the exhaust ports. It is therefore a; the r object of our invention to provide means for circulating eoola'nt between the'e'xh'aust phi-ts wherein the entrant admitted into the cylinder jacket space above the pert ahel by means hr partitions said latter spate to cause the coolant to first fi'otn downward between certain 'o'f the which t-thenee news upward between the remaining ptir'ts.

A further object of the invention is to pr-twine cy'lihde'r construction or a l op s-cavehsed'twm e'ycie engine in w'mt'h the eyiihuer is brmgihea w th thickehe'ci side wan in the section 'b'f the ports with annular cavities for j'cob1ahttircuIe-= tio'n bove ans below the putts, 'whit cavities are adapted to be closed by welded-t sih'sji b compl-et'e the Waiterjjatkt spacesjand aii nh'l exter surfaces or the-cylinder are designed t be 'iathe i v ,5 a A v These and otherthject's of "our invention" 1111 he more clearly understood from the i1 description of certain representative s embodying the same, in which rererneeismafie to the drawings, wherein; n a I Figure 1 is a l'on'gitu'linai se' through a cylinder unit ot an interhal to 111011 engine embbdy'ing the principals of the 1H- V'ention. a s. ,t

Figure '2 is a s ebt'i'onai View thkehsubstafitiamr on line 2 10f Figur 1. A v Figure 3 is an enlarged sectional view taken substantially on line 3+3 of Figure 1. I a

Figure 4; s a View similar to figure ibu't shewing a modificatitn tithe invention.

Figure 5 is a sectional view taken on the 5 of Figure ,s

Figure is an enlarged sectional View taken on line 6-4; of Figure 4; v t

v Referring now to the drawings, and first to Figures 1-3, there is shown an internal cefnbus tion engine having a crankcase 2 subfbormih cylinder unit indicated generally by the '4. The cylinder unit t'z'omprises a eynhaerb" e1 6 having a head 8 wh ieh'inay be fi'nidtbfl' 137 and Welded otherwise seoured'to the barrel 6 so as to form a single integral str'iieture The lower end I!) of the cylinder is crankcase fzby suitable means such age 'p p'f-spiittlamp ings :2 engaging r1" j 16 on the cylinder and crankcase "respe and drawn together by tie baits l8. 2B of the cylinder barrel 6 is fitted around the remainder of the cylinder circumference. As shown, both the inlet and the exhaust ports are inclined inwardly and upwardly of the cylinder through the thickened portion 24 to provide a smooth flow of air into and expulsion of the combustion gases out of the cylinder in carrying out the principals of loop scavenging in the most efiicient manner. Between each pair of adjacent exhaust ports 28 there is provided a longitudinal coolant passage 30, the lower ends of which open into an annular coolant collecting chamber or lower jacket space 32, andthe upper ends of the passages 36 open into another annular chamber 34 which constitutes the lower portion and the upper jacket space as will hereinafter more clearly appear. The lower jacket space 32 is formed as a radially outwardly opening groove in the thickened cylinder wall portion 24 just below the inlet and exhaust ports, which groove is closed by a separate jacket or casing 36 which is preferably welded in place to form a fluid-tight joint with the cylinder barrel. As shown, this lower casing 36 is set into the cylinder wall portion 24 so that the outer wall surface 36 of the latter and the outer periphery 40 of the casing 36 are flush with each other to provide a continuous cylindrical boss against which the lower mounting surface of the inlet and exhaust housing 42 is fitted. This housing 42 as will be seen in Figure 2 completely surrounds the cylinder and connects on opposite sides of the cylinder with the engine exhaust manifold 44 and the air supply manifold (not shown). Interiorly, the housing 42 is divided into inlet and exhaust chambers 43 and 45 serving the inlet ports 26 and exhaust ports 28, respectively. Its inner periphery is provided with upper and lower flanges 46 and 48 turned toward each other. The lower flange 48 closely fits the aforementioned lower jacket casing 36, in the outer wall of which is a. rubber O ring 50 or other suitable packing to provide a seal against escape of gases. The upper flange 46 is similarly sealed by an O ring 52 to the outer wall surface 38 of the cylinder portion 24 above the ports.

The annular chamber 34 above the ports is formed as an upwardly presenting groove in the upper end of the thickened cylinder wall portion 24 and the outer wall 54 of this chamber is extended by a welded-on annular jacket or casing 56 which has its upper end welded to the cylinder head 8. The cylinder head 8 has a cored jacket space 58 which is in direct communication with the upper cylinder jacket space formed between the cylinder wall 26 and the upper casing 56.

In addition to the jacketing of the cylinder and cylinder head it is also desired in engines of relatively large size or which are to be operated in closely confined spaces that the walls of all external exhaust passages be likewise jacketed, and for this purpose we have indicated the exhaust manifold 44 as having a double outer wall construction providing a coolant space 62 and the inlet and exhaust housing 42 with a coolant space 64, which latter extends preferably only around the exhaust chamber 45 of the housing 42. Coolant from a coolant manifold 6!] is piped first into the exhaust chamber coolant space 64 by a conduit 66, and after flowing through space 64 is transferred through a conduit 68 into the compartment of the cylinder immediately above the exhaust ports.

space 62 of the exhaust manifold 44. From the exhaust manifold coolant space 62 the coolant is returned through a second manifold (not shown) to the source. Thus a circuit is provided for the flow of coolant first through the inlet and exhaust housing jacket, thence into the cylinder jacket just above the ports and out through the cylinder head jacket to the exhaust manifold jacket. Before the coolant upon entering the cylinder jacket chamber 34 is allowed to rise into the cylinder head jacket 58, all or part of it is first made to pass through the passages 30 to efiect cooling of the exhaust ports 26. To effect this circulation through the passages 36 the chamber 34 is divided into compartments by partiticns I4, I6, 18 and 86. Partition I4 is in the form of a semiannular-plate which overlies the upper end of the chamber 34 around one half of the cylinder on the exhaust port side. This partion 74 may be secured in place in any desired manner as by welding at 82 to the upper end of the outer wall 54 of the chamber 34, and has its inner periphery closely fitting the outer surface of the inner wall of this chamber. Partitions 16, I8 and extend longitudinally from the partition I4 to the bottom of the chamber 34, and extend radially of the cylinder between the inner and outer walls of the chamber 34. Partitions 16 and 80 are diametrically opposite each other with respect to the cylinder, under the respective ends of the horizontal partition 14, and the partition I8 is located midway between partitions 16 and 80 on the exhaust side of the cylinder. Into the compartment 84 thus formed within the chamber 34 is admitted the coolant from the conduit 68 which is provided at its attachment to the cylinder with an angle fitting 86. This fitting, which may be formed integrally with the conduit 68 as shown, comprises a hollow tube having side walls 88 more or less closely fitting an opening 90 in the wall 54 and a partial end wall 92 which directs all or part of the incoming coolant through a notch 94 provided in the partition I6. The partition 80 has a similar notch 96 through which the coolant in chamber 96 may flow tangentially of the cylinder into the remainder of the cylinder jacket space toward the inlet side of the cylinder, in which latter space it may rise and eventually reach the cylinder head jacket space 58. In order to adapt each cylinder unit for installation on the crankcase so that the coolant may be introduced first to the chamber 98 and be discharged from the side of the cylinder head opposite port it, the outer wall 54 is provided with an opening I69 diametrically opposite to opening 90 and the cylinder head is provided with an opening I62 diametrically opposite opening 16 therein. With the cylinder unit 4 arranged on the crank-case 2 as shown these openings 560 and I02 are covered by cap'plates I64 and I06 respectively.

It will thus be seen that a full-flow coolant circuit may be provided by a closely fitting water inlet fitting 86 wherein all of the coolant enters the cylinder jacket just above the ports and first fiows downwardly between certain of the exhaust ports and thence returns between the remaining exhaust ports, before passing upwardly around the upper part of the cylinder and into the cylinder head coolant jacket. A very effective cooling of the exhaust ports is thereby obtained, and in engines in which the cylinder head temperatures are not excessively high the coolant. will have ample cooling capacity for cooling the cylinqer 1161 1, after having first cooled the exhaust emme messages. en gihe'sthaving meeii fer ieddi'tienall 'icylinder head'eoiihg, on the other new; the

water "inlet flitting: (8'5 inseyhave emery etting 'side walls =88 enil =heve -'ci'earence' he'tw'een the :partial end wall 92 emfi "the partition 76, thus :pr'o-Viding' an opening for apart o? the cooling water to fiow d-ireotly "to the -upiier pairt of cylinder without nest fiowving-tlownwarfi eetween the exhaustipdrts. I

In Figures 4- 6 is shbwn wmodifieaitien 'of the invention in which the coolant flowingto the cylin'der uni-t' divi'des into-eephralte zpeiths with ene :pontion entering the cylinder heed giacket 'FS'BECB 'dinetitl-y (without-first eoohn'g tl'ie exhaust sports) and another portion :ieilews the same circuit =between the e'xhamst. messages "as d-id ail- -of "the *COOh Ht-"ill :nreiiicius arrangement. ma this modificatien an @par'rts *c-f'the "assembly are the same as in Figures 1 3 with the exception'of the external r-piping :to and frem the cylinder imit and V the 'fect that "two identical angle fittings il Mend 1 21 are used instead 'df the sing-1e htung ae 0f the :former arrangement. Dhese fittings tlflend I21 are located in th openings 90 and 4% on diametrically opipesite sides of the eyl-inder end -fitting end partially-m the side wall er the opening in the wall '34. woolent thus entering the eompa/rtment 84 and flowing downward through the passages 60 between certain '01 the exhaust parts I28 into the iotver chamber '32 end returning thrbugh the other-passages 3U i'21EO compartment 98 is thus b1ec-ked by the fitting 42-8 from entering the remainder-0f the cylinder head jacket enctmust instead .pass eutwerdly of the 'cyl mder. I-twill be appreoiatedthat instead of theengle fittings 1:24! and I241, deified-holes in the cylinder nesting may 'beuseet.

The common cenduit N 29 receives the eoolant from the ceelant manifold-69; end a part of the coolant is taken off from this conduit Home, branch conduit $3 iea-dine to 'the ene side of the jacket space M of the inlet and exhaust housing 4 2-. he remainde'r'of the eeeieint in cenduit 129 subsequently divides intoe portion which ei'atei's the mung" M2 eemrected-to the cylinder "head hn'ening- 1e: and theremaining portion flows througha second branenpipe i3 1 having a ee'nneetion' M6- to "the cy1inde1' bar re1 at the fitting [*29. The Dining fer the return siee is enerally similar in that it 'eomnrise's'e eennee'hon .1 33 between the'd iseharge fitting m and a discharge conduit Wmwhichiatter joins a return 'conuuit 1 42 nom the exi'seher-ge one he 1e er the ween, end their heme-ion" 6.111; hit is sues'equentiyiemee a-i'efifii fi trench we Jeanine fiem the nalet end ie'xhe'iiist 1101133212 space ea end meiies e" eenneetitsn with the exhaust manifold j'eiiiz-et space 62 (from which "the coolant is eventually returned to its external source through a return coolant manifold not shewn). v

In this "div 'itied new" system the "seine effective coolingoi the exhaust ports is obtained-es in the"fu11 flow system, whileetthe semetinae ebteinz'ng a more effective owing of the eyiifider head, since a part of the coelent is initihllV-ihnagging-the "etinaui-ts 1211 hits the I lie t 1361- titirfs 6f the iehefi-ae" heeresned relative eeg-ree swinger hen sefiiQn'WyWe detainee. wrreienmseareeq iuitner eeemete theeeseectiife eeelanit new, eithei ot the return cehaeits l fines i$e i i(jviifed"wiith hi1 adifistaibl'e ife eietrne meaes ifi fihe teem 6f e -mentally set "meg siieh hs hofifin FM.

"We' eami. Eire, e v teinarcem lfiu fiiiiih ng-i l'ze ii' fthe --"Iik"e e s'i'de WaH .ereweeu i l ith e' eternity ef dt'rbtifir ferefitmuy spaced exhaust rfie'itis,-- cibitfit aiekets--she ieed "thinly exiee'eieig mferentielly reeylrneer eeoveenueerow end fidft's treeueme easeiamt: into and "returning 6601'- pei' j b'hee; Said sidewall eoqiemieesseees etween. eaeh peir "of ed'q-aeent-exheuem arts and interconnecting the tipper and flower a'cket fsiiasces, end it partition fiividing the impel meet sptt'ce into two circumiereritiai'ki; edieicent c's'on'maertm'e'x'its "whereby the -*-c'cc iaiit m titre e'omrhari tmnt may *enter the other hem-"part" 'nt' only my iivst iiassin'g downwardly e2- the eyhnder lih-reviigh the "iiasseges' *between cei'teiin exhaust 'liiort's to the' lewer jacket space --"md i hence upwartl'ly thi'ough the asasages between :the etifiai' 'ei'cha ust ports.

- 2-. "In a cb'eiing system ier 11 two c'ycie' enig-ine =ey1indei3, having a s'ide We'll provided with -a pinrenew-orewe-exhaust ii'orts and Eia'cket spaces extendingcireumferentieily of the bylinder above and below the ipbrts, 'cdo1ant inlet" and ontiet means eesociatee l "the *iitiiii'er ef said -fiecket fsneces; "said-side wali having coolant passages extending fongitudineily of the 'cylinder between wd 583091; exhaustieorts and interconnecting the 1 "miner end' iewer ijecket spaces, and a partition the ume-i gieeket space into circumfer- *entieliy eeifacmt cemmrtmen ts whereby coolant one cmiip'efirhii'e'nt may; enter the "other "compartment only by Way of shid iewer jacket space and "edit!" fpassefge'si 3. if! e (feeling sy'st'em foi" the ey Iinder end 'iaylirrder head of ":5, tw'mcyele inter-mi combustion engine 0?? the' l ikeih cylinder having a side wail aerev i-zled t enmity of 'circlmiferentialiy seamed exhaust ports anfiion gitudinal 'cooiant eaieseges between edgaeent poi-ts, means forming a eireumferentiei coolant fiacket for the cyliniier above ham ports end in communication with the umber ends oi said sphssages; ether 'meen's iewerends 6f med ates-sages, a, cylinder head hav "ine e-eeaient jeektih communication with the eminuer'aeeet, partition means within the c'yiin'der ieekethieeking direct eommuhieation benve'en eeitain hf ea-iii passages-arrathe cylin'iier iieae'iie'cket seia di iin'iet jacket having an inlet fereemtssien "ei' eoeiauttetween saiupartition queen's ee'd the gueeer -eiies i i "said certain e'aesagee; and ee e' dyl-ihier new iweket hating an eutiet tee I e eeexme eyetesnr ier the minder n ieei er e two eytle iiitrnal combustion *enei'e ortiie iikefh 'cyii-huei hevihg a side wen preview with e mute-Kw of cii'eumierntielh' spacezi exh-eust ne'rtsen'd iengituuinel assages 'iaetW-een augment ports, means ferining a cooling eket fbi the: cyl nder embve eeid perts, other said cylinder-jacket, partitions saidcylinder jacket forming two circumferentially adjacent compartments thereof, one of said compartments being in direct communication with the upper ends of only certain 'of said passages and the other compartment being in direct communication with the upper ends "of only the other of said passages, one of said compartments having an opening for the admission of coolant thereinto from an external supply source, the other of said compartments having an opening for the discharge of coolant into the remainder of said cylinder jacket, and means including an opening in the cylinder head jacket for the return of coolant to said supply source. v

5. In a cooling system for a two-cycle engine of the loop scavenge type, a cylinder" having a side wall provided with a plurality of circumferentially spaced exhaust ports, means forming a coolant jacket around the cylinder above the ports, a cylinder head closing the upper end of the cylinder and having a coolant jacket-in direct communication with said cylinder jacket, said side wall having passages extending longitudinally of the cylinder between adjacent pairs of exhaust ports, other means providing coolant communication between the lower ends of said passages, partition means within the cylinder jacket forming two circumferentially adjacent compartments thereof, one of said compartments being in direct communication with the upper ends of only certain of said passages, the other compartment being in direct communication with the'upper ends of only the others of said passages and with the remainder of the cylinder jacket,

an exhaust manifold for the engine, a housing surrounding the cylinder and connecting the exhaust ports to the manifold, said manifold and housing each being provided with a coolant jacket, conduit means for conducting coolant from an external source of supply to said housing jacket, from said housing jacket to said one compartment and from said cylinder head jacket to said manifold jacket.

6. In a cooling system for the cylinder and cylinder head of a two-cycle internal combustion engine or the like, a cylinder having a side wall provided with a plurality of circumferentially spaced exhaust ports and longitudinal passages between adjacent ports, means forming a coolant jacket for the cylinder above said ports, other means providing coolant communication between the lower ends of said passages, a cylinder head having a coolant jacket in communication with said cylinder jacket, partitions in said cylinder jacket forming two circumferentially adjacent compartments thereof, one of said compartments being in direct communication with the upper ends of only certain of said passages and the other compartment being in direct communication with the upper ends of only the other of said passages, one of said compartments having an inlet and the other having an outlet, said cylinder head jacket having an inlet and an outlet, and conduit means connecting said inletsand outlets to a source of coolant supply, said inlet connectin conduit means having relatively different capacities whereby the coolant supply to the cylinder head jacket is substantially greater than the supply to said one compartment.

'7. In a cooling system for a two-cycle engine of the loop scavenge type a cylinder having a side wall provided with a plurality of circumferentially spaced exhaust ports; means-forming a coolant jacket around the cylinder,"acylinder ihead'closing the upper end of the'cylinder and having a coolant jacket, said side wall having passages extending longitudinally of the cylinder between adjacent'pairs of exhaust ports, other means providing coolant communication between the lower ends of said passages, partition means fold, said manifold and housing each being prowithin the cylinder jacket forming two circumferentially adjacent compartments thereof, one of said compartments being in direct communication with the upper end of only certain of said passages, the other compartment being in direct communication with the upper ends of only the others of said passages, an exhaust manifold for the engine, a housing surrounding the cylinder and connecting the exhaust ports to the manivided with a coolant jacket, conduit means for conducting coolant from an external source to said cylinder head jacket, said one compartment and said housing jacket respectively, and" other conduit means for conducting coolant to said manifold jacket from said cylinder head jacket, said other compartment and said housing jacket respectively.

8. In a cooling system for the cylinder and cylinder head of a two-cycle internal combustion engine or the like, a cylinder having a side wall provided with a plurality of circumferentially spaced exhaust ports and longitudinal coolant passages between adjacent ports, means forming a circumferential coolant jacket for the cylinder above said ports, other means providing coolant communictaion between the lower ends of said passages'a cylinder head having a coolant jacket, partition means within the cylinder jacket blocking direct communication between certain of said passages and the remainder of said cylinder jacket, said cylinder jacket having an inlet for admission of coolant between said partition means and the upper ends of said certain passages, said cylinder jacket having an outlet for discharge of coolant from said remainder of said cylinder jacket, said cylinder head jacket having an inlet and an outlet for passage of coolant, means for conducting coolant from an external source of supply to said cylinder head jacket and cylinder jacket inlets respectively, and means for returning coolant to said source from said outlets.

9. In a cylinder structure for an internal combustion engine or the like having a side wall provided with a plurality of circumferentially spaced ports, coolant jackets spaced radially from and extending circumferentially of the cylinder above and below said ports, said side wall having coolant passages extending between adjacent ports and interconnecting the upper and lower jacket spaces, means for introducing coolant into and returning coolant from one of said jacket spaces, and a partition dividing said one jacket space into two circumferentially adjacent compartments whereby the coolant in one compartment may enter the other compartment only by first passing through the passages between certain of said ports to the other jacket space and thence through the passages between others of said ports.

ARNE J. HOVDE. WILLIAM ELMER BRILL.-

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,245,451 Fornaca' ;L' Nov. 6, 1917 I 1,526,574; Verhey l Feb. 1'7, '1925 1,625,843 Bowes Apr. 26, 1927 

